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| 2. |
- Heywood, I., et al.
(författare)
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Inflation of 430-parsec bipolar radio bubbles in the Galactic Centre by an energetic event
- 2019
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 573:7773, s. 235-237
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Tidskriftsartikel (refereegranskat)abstract
- The Galactic Centre contains a supermassive black hole with a mass of four million Suns1 within an environment that differs markedly from that of the Galactic disk. Although the black hole is essentially quiescent in the broader context of active galactic nuclei, X-ray observations have provided evidence for energetic outbursts from its surroundings2. Also, although the levels of star formation in the Galactic Centre have been approximately constant over the past few hundred million years, there is evidence of increased short-duration bursts3, strongly influenced by the interaction of the black hole with the enhanced gas density present within the ring-like central molecular zone4 at Galactic longitude |l| < 0.7 degrees and latitude |b| < 0.2 degrees. The inner 200-parsec region is characterized by large amounts of warm molecular gas5, a high cosmic-ray ionization rate6, unusual gas chemistry, enhanced synchrotron emission7,8, and a multitude of radio-emitting magnetized filaments9, the origin of which has not been established. Here we report radio imaging that reveals a bipolar bubble structure, with an overall span of 1 degree by 3 degrees (140 parsecs × 430 parsecs), extending above and below the Galactic plane and apparently associated with the Galactic Centre. The structure is edge-brightened and bounded, with symmetry implying creation by an energetic event in the Galactic Centre. We estimate the age of the bubbles to be a few million years, with a total energy of 7 × 1052 ergs. We postulate that the progenitor event was a major contributor to the increased cosmic-ray density in the Galactic Centre, and is in turn the principal source of the relativistic particles required to power the synchrotron emission of the radio filaments within and in the vicinity of the bubble cavities.
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| 3. |
- Camilo, F., et al.
(författare)
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Revival of the Magnetar PSR J1622-4950: Observations with MeerKAT, Parkes, XMM-Newton, Swift, Chandra, and NuSTAR
- 2018
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 856:2
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Tidskriftsartikel (refereegranskat)abstract
- New radio (MeerKAT and Parkes) and X-ray (XMM-Newton, Swift, Chandra, and NuSTAR) observations of PSR J1622-4950 indicate that the magnetar, in a quiescent state since at least early 2015, reactivated between 2017 March 19 and April 5. The radio flux density, while variable, is approximately 100 larger than during its dormant state. The X-ray flux one month after reactivation was at least 800 larger than during quiescence, and has been decaying exponentially on a 111 19 day timescale. This high-flux state, together with a radio-derived rotational ephemeris, enabled for the first time the detection of X-ray pulsations for this magnetar. At 5%, the 0.3-6 keV pulsed fraction is comparable to the smallest observed for magnetars. The overall pulsar geometry inferred from polarized radio emission appears to be broadly consistent with that determined 6-8 years earlier. However, rotating vector model fits suggest that we are now seeing radio emission from a different location in the magnetosphere than previously. This indicates a novel way in which radio emission from magnetars can differ from that of ordinary pulsars. The torque on the neutron star is varying rapidly and unsteadily, as is common for magnetars following outburst, having changed by a factor of 7 within six months of reactivation.
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| 4. |
- Biermann, Frank, et al.
(författare)
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Scientific evidence on the political impact of the Sustainable Development Goals
- 2022
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Ingår i: Nature Sustainability. - : Springer Nature. - 2398-9629. ; 5:9, s. 795-800
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Tidskriftsartikel (refereegranskat)abstract
- In 2015, the United Nations agreed on 17 Sustainable Development Goals as the central normative framework for sustainable development worldwide. The effectiveness of governing by such broad global goals, however, remains uncertain, and we lack comprehensive meta-studies that assess the political impact of the goals across countries and globally. We present here condensed evidence from an analysis of over 3,000 scientific studies on the Sustainable Development Goals published between 2016 and April 2021. Our findings suggests that the goals have had some political impact on institutions and policies, from local to global governance. This impact has been largely discursive, affecting the way actors understand and communicate about sustainable development. More profound normative and institutional impact, from legislative action to changing resource allocation, remains rare. We conclude that the scientific evidence suggests only limited transformative political impact of the Sustainable Development Goals thus far.
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| 5. |
- Caron, Bénédicte, et al.
(författare)
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IOIBD Recommendations for Clinical Trials in Ulcerative Proctitis : the PROCTRIAL Consensus
- 2022
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Ingår i: Clinical Gastroenterology and Hepatology. - : Elsevier. - 1542-3565 .- 1542-7714. ; 20:11, s. 2169-2627.e1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND AIMS: Clinical trials evaluating biologics and small molecules in patients with ulcerative colitis are predominantly excluding ulcerative proctitis. The objective of the PROCTRIAL (Definition and endpoints for ulcerative PROCtitis in clinical TRIALs) initiative was to develop consensus statements for definitions, inclusion criteria, and endpoints for the evaluation of ulcerative proctitis in adults.METHODS: Thirty-five international experts held a consensus meeting to define ulcerative proctitis, and the endpoints to use in clinical trials. Based on a systematic review of the literature, statements were generated, discussed, and approved by the working group participants using a modified Delphi method. Consensus was defined as at least 75% agreement among voters.RESULTS: The group agreed that the diagnosis of ulcerative proctitis should be made by ileocolonoscopy and confirmed by histopathology, with the exclusion of infections, drug-induced causes, radiation, trauma, and Crohn's disease. Ulcerative proctitis was defined as macroscopic extent of lesions limited to 15 cm distance from the anal verge in adults. Primary and secondary endpoints were identified to capture response of ulcerative proctitis to therapy. A combined clinical and endoscopic primary endpoint for the evaluation of ulcerative proctitis disease activity is proposed. Secondary endpoints which should be evaluated include endoscopic remission, histological remission, mucosal healing, histologic endoscopic mucosal improvement, disability, fecal incontinence, urgency, constipation, and health-related quality of life.CONCLUSION: In response to the need for guidance on the design of clinical trials in patients with ulcerative proctitis, the PROCTRIAL consensus provides recommendations on the definition and endpoints for ulcerative proctitis clinical trials.
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| 6. |
- Armitage, Emily G, et al.
(författare)
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Time-of-flight SIMS as a novel approach to unlocking the hypoxic properties of cancer
- 2013
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Ingår i: Surface and Interface Analysis. - 1096-9918 .- 0142-2421. ; 45:1, s. 282-285
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Tidskriftsartikel (refereegranskat)abstract
- It is known that hypoxia-inducible factor 1 (HIF-1) activity results in the coordinated up-regulation of a large number of proteins that facilitate cell survival in tumours; however, the effect of HIF-1 on cancer metabolism is less well characterised. With knowledge of the specific effect of HIF-1 on cancer metabolism, biomarkers could be identified for which new drugs could be targeted. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) offers the potential to analyse intact cells in situ and has a mass spectral coverage that is applicable to metabolic profiling. It has been used to analyse the effects of HIF-1 on multicellular tumour models. Multicellular tumour spheroids (MTSs) have been cultured from human colon carcinoma cells with and without the expression of HIF-1, and the surface of the cross sections of each MTS has been analysed. Because metabolic profiling is an emerging field in ToF-SIMS, there is a requirement to determine which metabolites can be detected using this technique and which of those can be identified in complex mixtures within biological samples. For this, a selection of metabolites have been analysed, and the ToF-SIMS standard spectra acquired have been used to localise metabolites in MTS sections. The comparison of metabolic profiles of MTSs with and without the expression of HIF-1 has elucidated potential biomarkers for tumour survival in hypoxia, some of which may be HIF-1 regulated.
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| 7. |
- Kotze, Helen L., et al.
(författare)
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ToF-SIMS as a tool for metabolic profiling small biomolecules in cancer systems
- 2013
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Ingår i: Surface and Interface Analysis. - 1096-9918 .- 0142-2421. ; 45:1, s. 277-281
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Tidskriftsartikel (refereegranskat)abstract
- Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is emerging as a tool for studying the metabolism of disease. ToF-SIMS enables chemical specificity in addition to high spatial resolution imaging of biological samples from cells to tissue. Here, ToF-SIMS has been used to investigate the metabolic regulation of hypoxia-induced chemoresistance to doxorubicin treatment using multicellular tumour spheroids. Imaging principal component analysis (PCA) was used as a tool to identify the regions of chemistry present within the image that differ as a result of drug treatment. A series of metabolite ToF-SIMS spectra were acquired, which were used to identify quasi-molecular ions and fragments correlated to the PCA loading plots. Metabolite patterns have been identified as potential biomarkers of hypoxia-induced chemoresistance.
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